Like tourists at a cruise-ship buffet, shrimp swarm a bacteria-rich sulfide chimney. The larger yellowish Chorocaris chacei are just as likely to eat their smaller brethren, transluscent shrimp called Rimicaris exoculata, or "rift shrimp without eyes." That's something of a misnomer. The bright reflective patches on the shrimp's backs have been found to contain rhodopsin, similar to the light-detecting pigment in human eyes. These patches may help the shrimp sense the glow emitted by scalding water at hydrothermal vents. If they go toward the glow, voilà, they find food.